Twisting and plying spindle balloon control



Dec. 3, 1957 A. w. VIBBER 2,814,925

TWISTING AND PLYING SPINDLE BALLOON CONTROL Filed Aug. 17, 1954 2Sheets-Sheet l INVENTOR.

Dec. 3, 1957 A. w. VIBBER 2,814,925

TWISTING AND FLYING SPINDLE BALLOON CONTROL Filed Aug. 17, 1954 2Sheets-Sheet 2 IN V EN TOR.

Wall/14L,

United States Patent O i TWISTING AND PLYING SPINDLE BALLOON CONTROLAlfred W. Vibber, Ridgewood, N. J;

Application August 17, 1954, Serial No. 450,358

21 Claims. (Cl. 57-583) This invention relates to the control of theballoon or free-flying loop of elongated flexible material present atballoon creating and maintaining twisting and/or plying mechanisms. Theinvention particularly relates to the control of balloons of spindles ofthe type wherein the material in the balloon is drawn from the ballooninto the rotating shaft or flyer which creates and maintains theballoon. Such type of elongated flexible material treating spindle isherein designated an infeeding twisting and/ or plying spindle.

This application is :a continuation-in-part of application Serial No.361,999, filed June 16, 1953, now Patent No. 2,736,160.

There are shown and described herein two species of the apparatus, asfollows: (1) Figs, 1 and 2; and (2) Fig. 3 Both embodiments are of theone-spindle twisting and plying system generally of the type shown inClarkson Patent No. 2,503,242, in which two strands are twisted togetherso as to form a two-ply strand, a first strand delivered from a supplythereof being ballooned about a let-off strand package from which thesecond strand is led.

The present invention represents an improvement over that described inmy prior application Serial No. 361,999, particularly Figs. 11 and 12 ofsuch prior application, wherein both the first and second strands arefed by synchronized positively driven feeding means. In the embodimentreferred to in my prior application, the tension in the balloon iscontrolled by a means engaging the balloon and detecting changes in theshape thereof and means responsive thereto to adjust the height of theballoon guiding eye above the flyer. The present invention provides asimplified means responsive to changes in the shape of the balloon tovary the tension of the strand issuing from the balloon and approachingthe plying junction, whereby the rates of absorption of the two strandsinto the plied strand may be controlled. As a result, when the balloonbecomes too large, the tension in the first strand, issuing therefrom,and approaching the plying junction is decreased, thereby to increasethe rate of absorption of the first strand, and when the balloon becomestoo small, the tension in the first strand issuing therefrom andapproaching the plying junction is increased, thereby to decrease itsrate of absorption. The balloon is thus maintained within apredetermined desired range of diameter :as well as degree ofwrap-around at the spindle.

The present invention has among its objects the provision of an improvedsimplified control for the balloon of twisting and plying mechanism.

A further object of the invention resides in the provision of a controlfor balloons of twisting and plying spindles of the infeeding type, suchcontrol being characterized by its simplicity of construction andmaintenance, by the fact that it is Wholly supported by the balloongenerating shaft, and by the fact that the cont-r01 is wholly mechanicalin nature.

2,814,925 Patented Dec. 3, 1957 ICE A still further object of theinvention lies in the pro vision of automatic strand tension controlmeans, wholly supported by the twisting and plying shaft of the spindle,for the strand leaving the balloon and approaching the plying junctionof apparatus wherein a first strand is ballooned about a source ofsupply of a second strand to ply the two strands together.

The above and further objects relating to economies of use andmanufacture will be more readily apparent upon consideration of thefollowing specification.-

My invention is clearly defined in the appended claims. Where parts are,for clarity and convenience, referred to on the basis of their orientedposition shown in the accompanying drawing, no limitation as topositioning of the entire structure is to be implied, since it will beunderstood that the entire structure may be inverted or that it may beused in any inclined position. Also in both the description and theclaims, parts at times may be identified by specific names for clarityand convenience, but such nomenclature is to be understood as having thebroadest meaning consistent with the context and with the concept of myinvention as distinguished from the pertinent prior art. The best formin which I have contemplated applying my invention isillustrated in theaccompanying drawing forming part of this specification, in which: i

Fig. 1 is a somewhat schematic view, partially in side elevation andpartially in vertical section, of a first embodiment of a one-spindlestrand plying mechanism in accordance with the invention.

Fig. 2 is a view in horizontal section through the flyer of the spindleof Fig. l, the section being taken along the line 22 in Fig. 1.

Fig. 3 is a view in horizontal section through the flyer of the spindleof the second embodiment of the invention, the section being taken in amanner similar to that of Fig. 2.

In the system shown in Figs. 1 and 2, the first strand, designated 10,proceeds from the first let-off package 11 downwardly through positivelydriven strand feeding means 12 driven in synch-ronism with the spindleshaft 14, in a manner to be described, into the balloon 15 created bythe flyer 16, which constitutes an enlarged head on shaft 14. The strand10 is drawn in through the flyer and meets the second strand 17 fed fromthe second letoff package 19 at the point P on the axis of the flyer,the two strands being plied together at point P so as to emerge as theplied strand or cord 20. The cord 20 is taken up by a conventionaltake-up mechanism 21, preferably ,one such as shown in Clarkson PatentNo. 2,503,242, which withdraws the cord and winds it on bobbin 22 underconstant tension.

Taking up now the instrumentalities which operate upon the strand 10 insuccession, the first let-off package 11 is preferably rotatably mountedon a support diagrammatically shown in Fig. 1 so as to present thestrand 10 opposite the feed-oif eye into the strand feeding capstansystem 12. Means 12 is made up of a first multi-grooved capstan 25 and asecond multi-grooved capstan .26 spaced therefrom, the two capstansbeing positively geared together so as to rotate at the same speed andin the same direction by means of a gear 27-on capstan 25, a gear 29 oncapstan 26, and the intermediate idle gear 3.0 meshing with the gears onthe capstans, all of such mechanism being carried on fixed framework(not shown). Means 12, which serves to deliver the strand 10 to theballoon at essentially constant speed, is positively driven insynchronism with spindle shaft 14 by the worm 31 on the bottom of shaft14, the worm gear 32 meshing therewith,

and mounted on shaft 34, the vertical shaft 35, and the upper horizontalshaft 36, shafts 34, 35, and 36 being geared together, all at a 1 X 1ratio, by bevel gears as shown, and shaft 36 being geared to capstan 26,also by bevel gears.

The fiyer 16 is in the nature of an enlarged head or flange on thetop'of the rotatable shaft 14. Shaft 14 is mounted to rotate in bearings37 in fixed frame parts 39 of the apparatus. The shaft 14 has its outersurface 40 between frame parts 39 crowned'to engage a driving belt (notshown), and serves as a means of creating and maintaining the balloon orfree-flying loop 15 in the strand 10, of supporting the second let-offpackage 19 on top of the fiyer 16 in substantially non-rotatingposition, and of plying the two strands and 17 together at the plyingpoint or junction P. Let-off package 19 is supported on a flange orplatform member 41 positioned on the upper, hollow shaft 42, the lowerend of shaft 42 being journalled in the fiyer 16 through themediurn .ofthe bearing 44. Platform 41 is eccentrically weighted at 45 so that,when the spindle shaft 14 is disposed at a small angle to the verticalthe weight 45 will seek the lower position and thus maintain the package19 and the shaft 42 substantially non-rotating even-though fiyer 16rotates at high speed. For ease of illustration the spindle shaft 14- isshown disposed vertically.

Thershaft 42 serves also as a support for a means 46 for feeding thestrand 17 from package 19 to the plying point P at essentially constantspeed. Means 46 consists of a magnetic ball tension device 47 having anon-magnetic seat 49 positioned across the upper end ofthe shaft 42, themagnetic ball 50 fitting within. such seat, the strand 17 progressingbetween the ball and the seat down into the shaft 42. A magnet 51positioned beneath seat member 49 maintains the ball 50 stably in itsseat. After leaving the magnetic ball tension device, the strand '17progresses into a radially outer groove on the idle upper multi-groovedfeeding capstan 52 journalled horizontally in shaft 42, and thenceproceeds downwardly to the confronting radially outer groove of thedriven lower multi-grooved capstan 54. Strand 17 then travels fromgroove to groove between capstans 52 and 54 until it reaches a centralgroove in driven capstan 54 from which it then travels verticallydownwardly to the plying point P.

Capstan 54,is driven in synchronism with the rotation of flyer 16 bymeans of the central hollow extension shaft 55 of the fiyer, shaft 55carrying a worm 56 on its upper end. Worm 56 meshes with the hourglassworm gear 57 journalled horizontally within shaft 42 at a positionradially displaced from the axis thereof. Worm gear 57 has on its outerends the small pinions 59 which mesh with the larger pinions 60 on theends of capstan 54. It will be apparent that rotation of the fiyer 16and thus of the, shaft 55 relative to the shaft 42 will positivelyrotate the multi-grooved capstan 54. With the proper choice of sizes andhand of the worm 56 and the worm gear 57, and the proper relative sizesof pinions 59 and 60, the strand 17 will be fed downwardly to the plyingpoint P at the same rate that strand 10 is fed into balloon 15.

The balloon in strand 10 is created and maintained by theballoon-generating-and-guiding axially concave pulley 61 positionedadjacent the outer end of the radial strand guiding passage 62 in thefiyer 16. As shown in Figs. 1 and 2, pulley 61 is mounted on areciprocable supporting member 64 which is mounted in a bore 65extending generally tangentially of the fiyer disc, and

which is urged in a clockwise direction with respect to.

the fiyer (Fig. 2) when the fiyer itself rotates clockwise, as indicatedby the curved arrow in Fig. 2, by the coil compression .spring 66 actingbetween the closed bottom 67 of the bore 66 and the piston-likeenlargement69 on the shank 70 of support 64. Support 64 is preventedfrom rotation with respect to the fiyer by the key 71 on its enlargement69 which engages in the longitudinally extending groove 72 in theconfronting side wall of bore 65. The pulley 61 is journalled on avertical axis between the upper and lower arms 74 at the forward end ofsupport 64, and can reciprocate from a forward position, with respect tothe flyer, wherein the forward end of enlargement 69 on support 64engages the bore-closing hollow internal nut 75, and in which thelongitudinally central forward edge of pulley 61 extends markedly intopassage 62, to one in which the longitudinally central forward edge ofthe pulley lies substantially flush with the rear wall of passage 62.

The pulley 61 constitutes the means whereby the fiyer 16 exerts force onthe strand 10 at the lower end of the balloon to create and maintainsuch balloon. Consequently, the spring 66 must exert at all times aforward force on pulley 61 which equals the rearwardly directed force Ron the pulley exerted thereon by the balloon. When the balloon (1) has aminimum diameter within the operative range, and thus a minimumwrap-around, the value of R is at a minimum. When the balloon (2) hasamaximum diameter within the operative range, and thus a maximumwrap-around, the value of R is at a maximum. The spring 66 is so chosenthat when the balloon is at condition (1) the enlargement 69 willhaveretreated at least slightly from nut 75, that is, pulley 61 willhave moved counterclockwise with respect to the fiyer, and that when theballoon is at condition (2) the pulley 61 will have retreatedlongitudinally appreciably further with respect to the flyer but notsufficiently to bring the longitudinally central forward edge portion ofthe pulley flush with the rear side wall of passage 62.

The pulley 61 thus constitutes a means for detecting changes in shape,that is, diameter and degree of wraparound, of the balloon 15. Theapparatus of the present invention, in both, illustrative embodimentsthereof, makes use of such changes in position of pulley 61 with respectto the fiyer to impose an added tension on strand 10 in the portionthereof which has left the balloon and is approaching plying junction P,such added tension being variable so that it is large when balloon 15 isat condition (1) and small when balloon 15 is at condition (2). .Theadded tension is generally additive to that existing in the portion ofstrand 10 in the balloon. The portion of strand 10 between the plyingpoint and. the added tension imposing means, therefore, is subjected tothe following total tension T at balloon condition (1):

' T (1) balloon (D'l added (1) andto the following total tension T atballoon condition (2):

i T (2) Tballoon (2)l' added (2 As we have seen,

balloon (2) T balloon (1) It is possible to make T at leastsubstantially constant, and thus T =T by appropriate construction of themeans which imposes the added tension on the strand. To promote greaterstability to the system, however, it is preferred that the curve oftotal tension T versus balloon diameter be somewhat drooping, that is,that T decreases somewhat as balloon diameter increases. The reason forthis will be apparent hereinafter.

In the embodiment of Figs. 1 and 2 the change of po' sition of pulley 61relative to the fiyer 16 is employed to alter the degree of deviationfrom a straight line path of travel of the strand 10 through passage 62by a snubbing abutment which is fixed relative to the fiyer, whereby tovary the added tension imposed on the strand. Tightly and nonrrotatablypositioned in a vertical opening 76 in fiyer 16 is a rounded abutmentmember 77, which may be made of a hard substance such as Carboloy,

the member 77 having its rear surface extending markedly into thepassage 62. Member 77 is so positioned that when pulley 61 is in itsforward position the strand passes sinuously about member 77 and pulley61, that when pulley 61 occupies a position corresponding to minimumoperative balloon diameter (1) such sinuous path has become slightlystraighter, and that when pulley 61 occupies a position corresponding tomaximum operative balloon diameter (2) such sinuous path becomes soflattened that it approaches a straight line. The guide pulley 61, inconjunction with abutment 77, functions to impose a markedly largerretarding tension on strand 10 when the ballon is at its minimumoperative diameter (1) than it does when the balloon is at its maximumoperative diameter (2) because the greater sinuosity of the path ofstrand '70 at such first condition causes the abutment 77 to impose agreater force on the strand transverse to its path of travel.

If the described means for imposing an added retarding tension on thestrand 10 were not employed, the greater tension in the strand in theballoon as the balloon expands, plus the greater friction imposed on itas it contacts the outer rear edge of the radial passage in the flyerdue to the increased wrap-around of the balloon, would cause the strand1G to approach the plying point under increased tension. Under suchcondition strand 1d acts as core at the plying point, and more of strandI67 than strand lid is absorbed into the plied strand or cord 20. Thusthe balloon tends to continue to expand, since such prior apparatus isnot self-compensating, until it becomes so large as to strike adjoiningstructures and thus to break.

The described mechanism for imposing a variable added tension on strand18 is such that the added tension falls off rapidly as the diameter ofthe balloon increases, so much so that the total tension in strand 10approaching the plying point decreases on a smooth curve from balloondiameter (1) to balloon diameter (2), in spite of the fact that thetension in the balloon proper increases as balloon diameter increases.The increased wraparound per so adds little or no back tension on thestrand since the balloon generator is a freely rotating pulley and not afixed surface on the flyer, as formerly.

With the apparatus of the invention, therefore, when the balloondiameter increases, the tension in strand 10 approaching the plyingpoint decreases relative to the tension in strand 17. Thus, the strand17 tends to become the core, more of strand 10 than of strand 17 isabsorbed into the plied cord, and the excess strand 10 in the balloon isrelatively quickly absorbed into the cord to return the balloon to itsoptimum diameter within its operating range. When the balloon decreasesin diameter from its optimum diameter, the tension instrand 10approaching point P increases. Strand 10 thus tends to become the core,more of strand 17 than of strand 10 is absorbed into the cord, thestrand 10 is withdrawn from the balloon more slowly than it is fedthereinto from package 13 by means 12, and thus the balloon is quicklyreturned to its optimum diameter.

In the-second embodiment of the invention, shown in Pig. 3, themechanism whereby variable retarding tension is imposed upon the firststrand is of a-somewhat different character. in Fig. 3, however, partswhich are similar to those in Figs. '1 andZ are designated by the samereference characters with an added prime. Itis to be understood that insuch second embodiment'flyer 16 of Fig. 3is substituted for the fiyer 16of Figs. 1 and 2.

The fiyer 16 of Fig. 3 has mounted therein the balloon generating pulley6 which is reciprocable in a direction normal to the radial passage 62in the flyer. Pulley 61 is rotatably mounted between upper and lowerarms 74' on the forward end of a rod 70'. Such rodor shank Ytl'has anenlargement69' thereon which reciprocates in the bore 79 in the flyer,the rod 70 beingurged toward passage 62 by :the coil compression spring66 acting between the rear of enlargement 69' and the.; forward innerface of annular nut 75' which slidably guides 6 the rear end of rod 70and is threadedly retained in the rear end of the bore 79. The pulley 61and its mounting rod 70' are thrust rearwardly, during rotation of theflyer, by the balloon which the pulley generates, the extent of rearwardtravel of the pulley with respect to the fiyer depending upon the degreeof wrap-around, and thus the diameter, of the balloon 15'. Such travelof the pulley 61 relative to the fiyer is caused to govern the amount ofadded tension imparted to the strand 10 by the following mechanism.Radially inwardly of the pulley 61 and in position to cooperate with thestrand 10' is a variable strand retarding means, generally designated83, which includes the retarding shoe 81, projecting into passage 62 andfixed with respect to the flyer, and the cooperating confrontingretarding shoe 82 mounted so that the strand 10 is pinched between theshoes. Shoe 82, which is in the form of a circular cylindrical cup, ismounted so that it is slidable, in the bore 84 in flyer 16, a shortdistance toward and away from shoe 81. The force with which shoe 82 isurged against the strand 10 as it is backed up by shoe 81 is determinedby the coil compression spring 89 in shoe 82, the spring, as shown,acting between the forward closed inner end of shoe 82 and the abutmentmember 86 contacting the rear end of spring 89. Spring 89 is somewhatsofter (exerts less compressive force) than spring 66. Abutment 86 is inthe form of an arm integral with and projecting sidewardly fromenlargement 69' on rod 70 into the interior of shoe 82 through a slot 85extending longitudinally of such shoe.

When the wrap-around of balloon 15 is at its desired operatin value theballoon forces pulley 61' backward somewhat with respect to the flyer,as shown in Fig. 3, so that enlargement 6% is spaced a short distancefrom stop shoulder 88 in bore 79. This draws abutment 86 rearwardly,thereby lessening the compression of spring 89 from its maximumcompression. Should the degree of wrap-around of the balloon 15 increasefrom such desired value, pulley 61', rod 70, and abutment 86 :are forcedrearwardly with respect to the flyer 16', thereby lessening the degreeof compression of spring 89 and thus lessening the retardation imposedon strand 10 by means 83. The means 83, springs 66' and 89, and pulley61 are so related that as the degree of wrap-around of balloon 15'increases the total retarding tension on strand 10 decreases. In otherwords, upon expansion of the balloon the decrease in the retardingtension imparted to strand It) by means 83 is greater than the increasein the .tension in strand 10 cause-d by the increased wraparound of theballoon.

Accordingly the system of Fig. 3 is stable, since upon undue balloonexpansion the second strand (17) becomes, in effect, the core, the rateof absorption of strand 10' into the plied cord is increased so that therate of withdrawal of the strand 10 from the balloon momentarily exceedsthe rate .at which the strand is fed into the balloon by means 12. Uponundue balloon contraction the strand 10 becomes, in effect, the core,.and the rate of its absorption into the plied cord is decreased,thereby to restore the balloon to its desired diameter.

In order not substantially to alter the path of strand 10 through means83 upon changes of the position of pulley 61 with respect to the flyer,there is providedan idle guide pulley 91 journalled in the flyer tomaintain strand 10' substantially axial of passage 62' in the pathbetween pulley 91 and plying point P. The parts of the supporting meansfor pulley 61', the abutment 86, and the shoe 32 may be introduced intothe indicated cavity in the fiyer 16 through an opening at the trailingedge of the flyer, such opening being thereafter closed by the member 90held on the flyer by at least one stud, as shown, and having a tongueand groove connection 92. at at least one edge of the member 90 and theedge of the cavity in the flyer cooperating therewith.

I claim:

Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of -a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first means for feeding thefirst strand into the loop, a second means for feeding the second strandto the junction where they are plied together, and means on the shafthaving a member engaging the first strand in the loop, said last namedmeans being responsive to changes in the shape of the loop to vary thetension in the first strand in the run thereof approaching the plyingjunction whereby to vary the relative rates of absorption of the firstand second strands into the plied strand.

. 2. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first substantially constantspeed means for feeding the first strand into the loop, a secondsubstantially constant speed means for feeding the second strand to thejunction where they are plied together, and loop-generating means on theshaft engaging the first strand at the end of the loop and responsive tochanges in the shape of the loop to vary the tension in the first strandin the run thereof approaching the plying junction whereby to vary therelative rates of absorption of the first and second strands into theplied strand.

3. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-olf packageand also to ply the two strands together, a first means for feeding thefirst strand into the loop, a second means for feeding the second strandto the junction where they are plied together, and strand retardingmeans on the shaft engaging the first strand at the end of the loop andresponsive to changes in the shape of the loop to vary the tension inthe first strand in the run thereof approaching the plying junctionwhereby to vary the relative rates of absorption of the first and secondstrands into the plied strand.

4. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first substantially constantspeed means for feeding the first strand into the loop, a secondsubstantially constant speed means for feeding the second strand to thejunction where they are plied together, and loopgenerating and strandretarding means on the shaft engaging the first strand at the end of theloop and responsive to changes in the shape of the loop to vary thetension in the first strand in the run thereof approaching the plyingjunction whereby to vary the relative rates of absorption of the firstand second strands into the plied strand so as to maintain the loopwithin a predetermined desired diameter range.

5. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first substantially constantspeed means for feeding the first strand into the loop, a secondsubstantially constant speed means for feeding the second strand to thejunction where they are plied together, and loop-generating and strandretarding means on the shaft engaging the first strand at the end of theloop and responsive to changes in the shape of the loop to vary thetension in the first strand in the run thereof approaching the plyingjunction whereby to vary the relative rates of absorption of the firstand second strands into the plied strand.

6. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-olf packageand also to ply the two strands together, a first means for feeding thefirst strand into the loop, a second means for feeding the second strandto the junction where they are plied together, loop-generating means onthe shaft responsive to changes in the shape of the loop, and strandretarding means on the shaft engaging the first strand in its passagefrom the loop therethrough, said last named means being controlled bythe loop-generating means to decrease the retardation imposed upon thefirst strand when the loop increases in degree of wrap-around and toincrease the retardation imposed upon the first strand when the loopdecreases in degree of wrap-around to vary the tension of the firststrand relative to the second strand in the portions thereof immediatelyapproaching the plying junction.

7. Mechanism for twisting together two strands so as to form a twoplystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first substantially constantspeed means for feeding the first strand into the loop, a secondsubstantially constant speed means for feeding the second strand to thejunction where they are plied together, loop-generating means on theshaft responsive to changes in the shape of the loop, and strandretarding means on the shaft engaging the first strand in its passagefrom the loop therethrough, said last named means being controlled bythe loop-generating means to decrease the retardation imposed upon thefirst strand when the loop increases in degree of wrap-around and toincrease the retardation imposed upon the first strand when the loopdecreases in degree of wrap-around to vary the tension of the firststrand relative to the second strand in the portions thereof immediatelyapproaching the plying junction, whereby to vary the relative rates ofabsorption of the first and second strands into the plied strand so asto maintain the loop within a predetermined desired diameter range.

8. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-olf packageand also to ply the two strands together, a first means for feeding thefirst strand into the loop, a second means for feeding the second strandto the junction where they are plied together, and strand retardingmeans on the shaft engaging the first strand in its passage from theloop therethrough, said last named means being operative in response tochanges in the shape of the loop to decrease the retardation imposedupon the first strand when the loop increases in degree of Wrap-aroundand to increase the retardation imposed upon the first strand when theloop decreases in degree of wrap-around to vary the tension of the firststrand relative to the second strand in the portions thereof immediatelyapproaching the plying junction, the strand retarding means being soconstructed and arranged that as the degree of wrap-around of the loopincreases the total tension in the first strand approaching the plyingjunction decreases and as the degree of wrap-around of the loopdecreases the total tension in the first strand approaching the plyingjunction increases.

9. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first substantially constantspeed means for feeding the first strand into the loop, a secondsubstantially constant speed means for feeding the second strand to thejunction where they are plied together, and strand retarding means onthe shaft engaging the first strand in its passage from the looptherethrough, said last named means being operative in response tochange in the shape of the loop to decrease the retardation imposed uponthe first strand when the loop increases in degree of wrap-around and toincrease the retardation imposed upon the first strand when the loopdecreases in degree of wrap-around to vary the tension of the firststrand relative to the second strand in the portions thereof immediatelyapproaching the plying junction, the strand retarding means being soconstructed and arranged that as the degree of wrap-around of the loopincreases the total tension in the first strand approaching the plyingjunction decreases and as the degree of wrap-around of the loopdecreases the total tension in the first strand approaching the plyingjunction increases.

10. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first means for feeding thefirst strand into the loop, a second means for feeding the second strandto the junction where they are plied together, a yieldable loopgenerating strand engaging means on the radially outer portion of theshaft adjacent the end of the loop, means resiliently urging the loopgenerating means against the first strand in the direction of rotationof the shaft, and means on the shaft engaging and retarding the firststrand and responsive to changes in the shape of the loop to vary thetension in the first strand in the run thereof approaching the plyingjunction whereby to vary the relative rates of absorption of the firstand second strands into the plied strand.

l1. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-ofi strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first substantially consantspeed means for feeding the first strand into the loop, a secondsubstantially constant speed means for feeding the second strand to thejunction where they are plied together, a yieldable loop generatingstrand engaging means on the radially outer portion of the shaftadjacent the end of the loop, means resiliently urging the loopgenerating means against the first strand in the direction of rotationof the shaft, means on the shaft engaging and retarding the first strandand responsive to yielding of the loop generating means with respect tothe shaft to vary the retardation imposed on the first strand in the runthereof approaching the plying junction whereby to vary the relativerates of absorption of the first and second strands into the pliedstrand so as to maintain the loop within a predetermined desireddiameter range.

12. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a balloon of the first strand and also to ply the twostrands together, a first substantially constant speed means for feedingthe first strand into the balloon, a second substantially constant speedmeans for feeding the second strand to the junction where they are pliedtogether, and variable retarding means for the first strand,

said last named means comprising a balloon-generating strand-engagingroll on the radially outer portion of the shaft adjacent the end of theballoon, means mounting the roll for limited reciprocation with respectto the shaft in a direction generally normal to a radial axial planethrough the shaft, means urging the roll forward with respect to theshaft in the direction of rotation of the shaft, a strand snubbingmember close to the roll and fixed with respect to the shaft, the firststrand in its travel from the balloon and radially inwardly of the shaftto the plying junction following a sinuous path over the forward surfaceof the roll and thence over the rear surface of the snubbing member.

13. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a balloon of the first strand and also to ply the twostrands together, a first substantially constant speed means for feedingthe first strand into the balloon, a second substantially constant speedmeans for feeding the second strand to the junction where they are pliedtogether, and variable retarding means for the first strand, said lastnamed means comprising a balloon generating strand engaging roll on theradially outer portion of the shaft adjacent the end of the balloon,means mounting the roll for limited reciprocation with respect to theshaft in a direction generally normal to a radial axial plane throughthe shaft, means urging the roll forward with respect to the shaft inthe direction of rotation of the shaft, means comprising a pair ofrelatively movable strand compressing members on the shaft engaging the,

first strand in its passage radially inwardly of the shaft to the plyingjunction, means urging such members relatively toward each other, andmeans responsive to movement of the roll with respect to the shaft tovary the last named means so that as the roll is progressively forcedrearwardly with respect to the shaft by the balloon the strandcompressing members engage the strand with a progressively smallerforce.

14. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shafthaving a fiyer operable to rotate a loop of the first strand about thelet-off package and also to ply the two strands to gether, a first meansfor feeding the first strand into the loop, a second means for feedingthe second strand to the junction where they are plied together, andstrand tensioning means on the fiyer engaging the first strand andresponsive to changes in the shape of the loop to vary the tension inthe first strand in the run thereof approaching the plying junctionwhereby to vary the relative rates of absorption of the first and secondstrands into the plied strand.

l5. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a, rotatableshaft having a fiyer operable to rotate a loop of the first strand aboutthe let-off package and also to ply the two strands together, a firstsubstantially constant speed means for feeding the first strand into theloop, a second substantially constant speed means for feeding the secondstrand to the junction where they are plied together, and strand tensioning means on the. fiyer engaging the first strand and responsive tochanges in the shape of the loop to vary the tension in the first strandin the run thereof approaching the plying junction whereby to vary therelative rates of absorption of the first and second strands into theplied strand.

l6. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a letoff strand,

package for a second strand, a rotatable shaft having a fiyer, operableto rotate a loop of the first strand about the let-off package and alsoto ply the two strands together, a first means for feeding the firststrand into the loop, a second means for feeding the second strand tothe junction where they are plied together, and loop-generating andstrand retarding means on the fiyer responsive to changes in shape ofthe loop and engaging the first strand in its passage from the looptherethrough, said last named means being so constructed and arranged asto decrease the retardation imposed upon the first strand when the loopincreases in degree of wrap-around and to increase the retardationimposed upon the first strand when the loop decreases in degree ofwrap-around whereby to vary the tension of the first strand relative tothe .second strand in the portions thereof immediately approaching theplying junction.

17. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shafthaving a fiyer operable to rotate a balloon of the first strand and alsoto ply the two strands together, a first substantially constant speedmeans for feeding the first strand into the balloon, a secondsubstantially constant speed means for feeding the second strand to thejunction where they are plied together, and variable retarding means forthe first strand, said last name-d means comprising a balloon-generatingstrand-engaging roll on the radially outer portion of the fiyer adjacentthe end of the balloon, means mounting the roll for limitedreciprocation with respect to the fiyer in a direction generally normalto a radial axial plane through the fiyer, means urging the roll forwardwith respect to the flyer in the direction of rotation of the fiyer, astrand snubbing member close to the roll and fixed with respect to thefiyer, the first strand in its travel from the balloon and radiallyinwardly of the fiyer to the plying junction following a sinuous pathover the forward surface of the roll and thence over the rear surface ofthe snubbing member.

18. A strand twisting mechanism, comprising a driven shaft for rotatinga loop of a strand, means for feeding the strand into the loop, meansfor withdrawing the strand from the loop in a run extending at leastgenerally radially of the shaft, and strand engaging means on the shaft,said last named means including means for generating the loop and forimposing a first retarding tension on the generally radial run of thestrand when the loop is of a small size and for imposing a progressivelysmaller retarding tension on such run as the loop increases in size.

.19. A strand twisting mechanism, comprising'means for rotating andguiding a loop of a strand, means for feeding the strand into the loop,and means for withdrawing the-strand from the loop, in a run extendingat least generally radially of the means for rotating and guiding theloop, the loop rotating and guiding means including means for imposingafirst retarding tension on the generally radial run of the strand whenthe loop is of a small size and for imposing a progressively smallerretarding tension on such run as the loop increases in size.

20. Mechanism for twisting together two strands so as to form a two-plystrand, comprising a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, means forrotating and guiding a loop of the first strand about the let-offpackage and also to ply the two strands together at a plying junction,means for feeding the first strand into the loop, means for feeding thesecond strand to the plying junction, and means to withdraw the pliedstrand from the plying junction, the run of the first strandwithdrawnfrom the loop and approaching the plying junction beingmaintained at least generally radially of the loop rotating and guidingmeans, the loop rotating and guiding means including means for imposinga first retarding tension on the generally radial run of the-firststrand approaching ing the strand from the loop in a run extending atleast 7 generally radially into the shaft, and strand engaging means onthe shaft, said last named means including means i for generating theloop and means for deflecting and when the loop is of a small diameterand to impose a progressively smaller retarding tension thereon as theloop increases in diameter.

References Cited in the file of this patent UNITED STATES PATENTS

